Heat exchanger assembly

ABSTRACT

A heat exchanger assembly for a refrigerator is provided and includes a pipe line that extends on a thermally conductive substrate and is divided by a throttle point into an evaporator and a condenser.

The present invention relates to a heat exchanger assembly comprising a pipeline which extends on a thermally conductive substrate. Heat exchangers with a design of this type are common in refrigeration construction as evaporators for cooling an interior of a refrigerator by coolant that evaporates in the pipeline at low pressure.

A second type of heat exchanger used in a refrigerator is the condenser in which, at high pressure, the coolant condenses to the environment while dissipating heat.

These two heat exchangers must be joined to a compressor when the refrigerator is assembled to form a hermetically tight coolant circuit.

The aim of the present invention is to create a heat exchanger assembly for a refrigerator which allows the construction of a coolant circuit with reduced complexity.

The object is achieved in that in a heat exchanger assembly comprising a pipeline which extends on a thermally conductive substrate, the pipeline is divided by a throttle point into an evaporator and a condenser.

According to the present invention it is therefore sufficient to provide or form a single pipeline, embodied in one piece, on a substrate in order to thus immediately obtain both refrigerator heat exchangers. Conventionally required assembly steps for connecting the heat exchangers to each other are omitted. Furthermore, the monolithic implementation of the two heat exchanger assemblies simplifies installation of the heat exchangers in a housing as only a single assembly has to be positioned and secured instead of two separate heat exchangers and a line connecting them.

The substrate preferably comprises two plate-like sections joined by a curved coupling piece, the evaporator being arranged on a first section and the condenser on a second section. The individual sections can therefore be made so as to have the same large size and, if necessary, each individual one of them can have the dimensions of a housing wall of the refrigerator.

According to a preferred embodiment the plate-like sections meet each other at a right angle on the coupling piece. It is thereby possible to place the sections on different walls of the refrigerator housing respectively, in particular on a back wall and a side wall. In the surroundings of the coupling piece the plate expediently extends through an insulating layer of the refrigerator housing, so the evaporator comes to rest on the inside and the condenser on the outside of the insulating layer.

The coupling piece is expediently locally perforated to limit heat exchange between condenser and evaporator.

The throttle point then expediently extends over the coupling piece.

To form the throttle point the pipeline can be locally indented. A uniform, contiguous pipeline in particular can therefore be used for the evaporator and condenser.

A downstream pipe section of the condenser and/or a pipe section in which the throttle point is formed preferably run(s) adjacent to a downstream pipe section of the evaporator. Coolant circulating in the downstream pipe section of the evaporator can thus pre-cool in the downstream pipe section of the condenser or coolant circulating [in] the pipe section of the throttle point can pre-cool before it enters the evaporator.

The invention also relates to a refrigerator comprising a housing and a heat exchanger assembly of the type defined above. In a refrigerator of this kind the evaporator and the condenser are arranged on adjacent walls of the housing or on an identical wall.

Further features and advantages of the invention emerge from the following description of exemplary embodiments with reference to the accompanying figures, in which:

FIG. 1 shows a schematic perspective view of a refrigerator comprising a heat exchanger assembly according to the invention;

FIG. 2 shows an enlarged section through a corner of the refrigerator housing;

FIG. 3 shows a section through the throttle point of a heat exchanger assembly according to the invention; and

FIG. 4 shows a plan view of a second embodiment of a heat exchanger assembly according to the invention.

In a semi-transparent view FIG. 1 shows a refrigerator in a design that is known per se, comprising a body 1, a door 2 and a recess 3, relieved in a lower back region of the body 1, in which a compressor is accommodated. A heat exchanger assembly comprises a condenser 4, which is exposed at the back of the body 1 and for the most part fills this back above the recess 3, as well as an evaporator 5 which extends along a side wall of the body 1 in the immediate vicinity of its interior. The heat exchanger assembly has a one-piece sheet metal substrate 15 in the form of a plate bent along one vertical edge 6 and made, for example, from aluminum. A pipeline 7 extends in one piece over this sheet metal substrate from an inlet 8 of the condenser to an outlet 9 of the evaporator 5. The pipeline 7 crosses the vertical edge 6 in the vicinity of its upper end. As a result of the course bent at the edge 6 the pipeline 7 forms a throttle 10 at this point, at which the pressure of the circulating coolant drops abruptly. As the coolant in the part of the pipeline 7 located upstream of the throttle 10 is subject to high pressure, this part acts as a condenser, while the part located downstream and subject to low pressure acts as the evaporator.

FIG. 2 shows a horizontal section through the throttle 10 and its surroundings in two mutually parallel planes I, II. A boundary between the two planes is indicated by a dash-dot line in FIG. 2. To the right above the line cutting plane I runs through the pipeline 7; to the left and below cutting plane II runs above the pipeline 7. The throttle 10 is produced by firstly securing the pipeline to the initially still level sheet metal substrate by gluing or soldering and then bending the sheet metal substrate together with the pipeline 7 secured thereto in order to form the vertical edge 6. This shaping inevitably leads to flattening of the pipe 7 at the edge 6 and to a narrowing of its cross-section.

Whereas in the cutting plane I running at the level of the pipeline 7 the sheet metal substrate extends continuously between condenser 4 and evaporator 5, in order to force the narrowing of the pipeline 7 when it is bent, outside of this plane cutouts 11 are formed in the sheet metal substrate which weaken it along the vertical edge 6 and thus promote the formation of a sharp bend. Cutting plane II runs through one such cutout 11. The cutouts 11 are effective moreover in limiting the heat flux across the sheet metal substrate between condenser 4 and evaporator 5 and between the environment and the interior of the refrigerator.

Whereas the condenser 4 is located on the outside of an insulating material layer 12 of the back wall, an edge strip 13 of the evaporator 5 that adjoins the vertical edge 6 extends through this insulating material layer 12, so the main part of the evaporator 5 runs on the inside of the insulating material layer, in direct contact with an inner receptacle wall 14.

Instead of forming a throttle by way of bending of the pipeline 7 at a boundary between condenser and evaporator, as shown in FIG. 2, it can also be formed in a planar section of the pipeline 7 by local flattening of the pipeline. FIG. 3 shows a section through a throttle point 10 which is obtained by flattening the pipeline 7 with the aid of a die or in this case a narrow blade running parallel to the pipeline 7. The drop in pressure at such a throttle point 10 can be precisely controlled by varying its length. In particular it is easily possible to subsequently lengthen such a throttle point 10 on a finished heat exchanger assembly if the drop in pressure attained at it proves to be inadequate. Such a throttle point 10 obtained by flattening can be formed in particular at the section of the pipeline 7 that crosses the edge strip 13 in FIG. 2.

FIG. 4 shows a plan view of a modified embodiment of a heat exchanger assembly according to the present invention in a planar state prior to installation in a refrigerator. The sheet metal substrate 15 of this heat exchanger assembly is divided by two groups of cutouts 11 into condenser 4, evaporator 5 and a coupling piece in the form of a narrow strip 16 extending between condenser 4 and evaporator 5. The pipeline 7 runs from the inlet 8 in the bottom left-hand corner of the sheet metal substrate 15 initially in meanders from top to bottom across the entire condenser 4 and then crosses to the strip 16, runs upwards over the entire length thereof and then in meanders from top to bottom across the evaporator 5. The pipeline 7 then runs upwards again in order to switch back to the strip 16 in the vicinity of the upper end thereof and to run downwards on the strip to the outlet 9. Therefore two parallel pipeline sections 17, 18 run on the strip 16, insulated from both the condenser 4 and evaporator 5 by the cutouts 11. Coolant, which in section 17 aspires to the throttle 10 formed at the entrance to the evaporator 5, is thus pre-cooled in counter flow by coolant flowing out of the evaporator 5 via section 18. A low temperature at the downstream end of the throttle 10 is therefore achieved on the one hand, and on the other hand it is ensured that coolant issuing from the heat exchanger assembly at outlet 9 is sufficiently warm that there need be no concern about dew forming on a pipeline extending from the outlet 9 to the compressor.

A vertical edge 6 can be formed by right-angled bending of the sheet metal substrate 15 along a group of cutouts 11, which edge allows the heat exchanger assembly to be installed as shown in FIG. 1. Bending the sheet metal substrate along the two groups of cutouts 11 produces mutually parallel condenser and evaporator, which for example can both be placed on the back wall of the refrigerator, the gap between condenser 4 and evaporator 5 then being filled with the foam of the insulating material 12. 

1-9. (canceled)
 10. A heat exchanger assembly for a refrigerator, the heat exchanger comprising: a thermally conductive substrate; and a pipeline, the pipeline having a continuous extent on the thermally conductive substrate and a throttle point on the continuous extent of the pipeline, the throttle point demarcating the continuous extent of the pipeline between a portion forming an evaporator leading to the throttle point and a portion forming a condenser leading from the throttle point.
 11. The heat exchanger assembly as claimed in claim 10, wherein the substrate includes a first plate-like section and a second plate-like section, the first and second plate-like sections is joined by a curved coupling piece, the evaporator is arranged on the first plate-like section, and the condenser is arranged on the second plate-like section.
 12. The heat exchanger assembly as claimed in claim 11, wherein the plate-like sections meet each other at a right angle on the coupling piece.
 13. The heat exchanger assembly as claimed in claim 11, wherein the coupling piece is perforated at several locations.
 14. The heat exchanger assembly as claimed in claim 10, wherein the throttle point extends over the coupling piece.
 15. The heat exchanger assembly as claimed in claim 10, wherein the pipeline is configured as a single piece and is indented at a selected location to form the throttle point.
 16. The heat exchanger assembly as claimed in claim 10, wherein one of a downstream pipe section of the condenser or a pipe section in which the throttle point is formed runs adjacent to a downstream pipe section of the evaporator.
 17. A refrigerator comprising: a housing having a pair of adjacent walls; and a heat exchanger assembly including a thermally conductive substrate and a pipeline, the pipeline having a continuous extent on the thermally conductive substrate and a throttle point on the continuous extent of the pipeline, the throttle point demarcating the continuous extent of the pipeline between a portion forming an evaporator leading to the throttle point and a portion forming a condenser leading from the throttle point, and the evaporator and the condenser being arranged on adjacent walls of the housing.
 18. A refrigerator comprising: a housing having at least one wall; and a heat exchanger assembly including a thermally conductive substrate and a pipeline, the pipeline having a continuous extent on the thermally conductive substrate and a throttle point on the continuous extent of the pipeline, the throttle point demarcating the continuous extent of the pipeline between a portion forming an evaporator leading to the throttle point and a portion forming a condenser leading from the throttle point, and the evaporator and the condenser being arranged on the same respective wall of the housing. 